Conical-diaphragm sound reproducer



5, 1929. c. w. PETERSON- v CONICAL DIAPHRAGM SOUND REPRODUCER Filed Dec. 10,1924

, VII/II ///IIIIIIIII/ INVENTOR.

ATTORNEYS Patented Nov. 5, 1929 CHARLES WQPETERsoN, or ANN ARBOR, MICHIGAN CONICAL-DIAPHRAGM SOUND REPRODUCER Application filed December 10, 1924. Serial No. 755,056.

My invention relates to devices for reproducing sound under impelled oscillations, such as imparted by the armature of an electro-magnetic receiver in radio receiving sets. It has as its object a simple structure, which can be manufactured in quantities at low the entire device is free to move, and the rim is lightly en aged by material which serves merely to ho d the cone in shape and permitit to move in a resilient manner, and to absorb such oscillations or prevent the formation of oscillations which cause fluttering of the coneedge.

I accomplish my objects by that certain construction and arrangement of parts to- 2 be hereinafter more specifically pointed out and claimed.

In the drawings: Figure 1 is a front elevation of the device. 1 Figure 2 is a central vertical section thereof on the line 22 of Figural.

Figure 3 is a detail device. I Figures 4 to 6 inclusive are further details of modified ways of providing for afreely 3 vibrating peripheral support for the conical diaphragm. 4

In providing a framework for my'device I have endeavored to simplify itas. much as possible;

I provide a metal casting having a base '1, with a ring extending upwardly from the base, as at 2. Also extending up from the base in front of the ring is a standard 3, which divides into two arms 4, 4:, and which 5 arms have secured across between them a supporting plate 5 for a receiver or transmitter having a vibrating armature.

In the preferred form the diaphragm is formed of parchment paper, in a cone 7, at the apex of which is mounted by means of a section of a modified pair of small metal cone pieces 8, a socket 9.- The vibrating Wire. 10 fromtne armature is held in this socket piece 9, as by a set screw. This links thecent er of the diaphragm to the armature.

The cone is held in place so as to vibrate Without false lines of strain or distortion and without undesired overtones by gripping it over the Wire 10, by means of the set screw, as shown, and as a preferred, edge or peripheral protection the ring 2 i's formed with a hollow, front face, and the clamping ring 12 is bolted to it so as to hold a channel piece 13, of felt or the like. The unbroken periphery of the diaphragm is set into light contact with the felt channel so as to merely rest in place, without any metal contact.

In'Figure 3 the ring 20 taking the place of ring 2 is illustrated as having a half circle form, with the cavity facing inward. This cavity is filled with a resilient aperiodic material 20, such as dry cotton or spongy rubber, and the diaphragm 21, in the form of a cone is merely set in place by permitting its periphery to slightly touch against the exposed face of the resilient filling. The use of felt is preferred because of its characteristic aperiodic nature and the action of the fibres thereof in preventing fluttering to develop in the cone.

In Figure 4 the ring corresponding to ring 2 is shown at 50, having a concave cross section, terminating in an upward flange 51. The clamping ring .52 has a like conformation. A pair of rings 53 of rubber or some. other flexible or resilient medium, are set over theunbroken edge of the diaphragm 54, and held in place by screwing the two flanges of the rings together over the rings. of rubber 53. i

In Figure 5 tlfe ring 7 0 faced, for neatness, with a rlng 71, as in the last instance, is provided with a ring 72 of cotton wool or the like, cemented to its rearward .face.

The diaphragm 73 having unbroken periphery, is pulled with its edge against the cotton wool facing to the back of the ring 7 O, by means of the connector 7 4 with the armature. The edge in this instance is free to vibrate slightly, and to slide slightly, as a result of impressed oscillations at its center.

In Figure 6 the opposite relation is shown in which the ring 80 is a plain ring, and the attached ring 81 has the felt or other resilient material facing 82. In this case the connection 83 with the armature is adjusted to push the center of the cone 84 away from the armature, thereby holding it against the felt facing on its outer, unbroken edge.

It is evident that the various forms illustrated are merely a series of ways of accomplishing my main object, and that other ways could be devised which would likewise meet my purpose. I do not insist on the diaphragm being composed of the precise substance described as other non-metallic or resilient .metallic substances would serve.

I claim as new and desire to secure by Lettherefor, and a body of resilientfelt deaden- Y ters Patent, is A 1. In a loud speaker having a receiver with a diaphragm connection, a cone of light, vibrant material exposed to unconfined air,- mounted at its apex on the diaphragm connection and an aperiodic substance engaging the periphery of the cone. and having sufficient mass to prevent oscillations at the rim of the cone other than those oscillations due to sound generating movement of the cone imparted by the receiver.

2. In a sound reproducer, the combination with a receiver having a diaphragm connection, of a light, vibrant cone secured to said diaphragm connection, a frame and support therefor, and a body of resilient felt deadening material held on said frame, said cone being so mounted on the diaphragm connection as to touch lightly against the deaden ing material, forming an aperiodic engaging means for the periphery of the cone, without interfering with sound generating movements of the cone imparted by the receiver. 3. In a sound reproducer. the combination with a receiver having a diaphragm connection, of a light, vibrant conesecured to said diaphragm connection, a frame and support ing material held on said frame, saidscone being so mounted on the diaphragm connection as to rest lightly against'tlre deadening material, forming an aperiodic engaging means for the periphery of the cone, without vements of the cone as a whole with low od vibrations, said frame bein formed as aring on-the support, and a facmg ring to conceal the of the cone detachably secured to the ring andlying out of contact with the cone.

4. In a loud speaker the combination with a receiver having a diaphragm connection,

of a light vibrant cone supported at its apex on the diaphragm connection, and aperiodic means about the entire rim of the cone "pre-. venting rim distortions and hence fluttering withoutrmterfering with movements of the cone as a whole, and without impartin inmotor, a frame and connections arranged to 7 hold the driving motor and diaphragm in proper relation and having a rim projecting beyond the edge of the diaphragm, and an aperiodic material disposed between the edge of the diaphragm and the rim and in contact with both.

8. In a loud speaker, a conical diaphragm supported in free access to air, a driving motor, a frame and connections arranged to hold the driving motor and diaphragm in proper relation and having a rim projecting beyond the edge of the diaphragm, and an aperiodic material disposed between the edge of the diaphragm and the rim and in contact with both, said aperiodic material being soft and flexible enough to allow free sound generative motion of the diaphragm at the edge.

9. In a loud speaker, a conical diaphragm supported in free access to air, a driving motor, a frame and connections arranged to hold the driving motor and diaphragm in proper relation and havinga rim projecting beyond the edge of the diaphragm, and an aperiodic material disposed between the edge of the diaphragm and the rim and incontact with both said aperiodic material being soft and flexible enough to allow free sound gen- 

